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// Copyright 2016 Google Inc. All Rights Reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
#include "base/callback.h"
#include "base/memory/scoped_ptr.h"
#include "base/synchronization/waitable_event.h"
#include "base/threading/thread.h"
#include "cobalt/storage/savegame.h"
namespace cobalt {
namespace storage {
// The SavegameThread wraps a Savegame object within its own thread in order to
// enable asynchronous writes to the savegame object.
class SavegameThread {
explicit SavegameThread(const Savegame::Options& options);
// Returns the savegame data that existed on disk on startup. This method
// should only be called once, as the data will be released after it is
// called.
scoped_ptr<Savegame::ByteVector> GetLoadedRawBytes();
// Flush data to be written to the savegame file. The write will happen
// asynchronously on SavegameThread's I/O thread, so this method will return
// immediately.
void Flush(scoped_ptr<Savegame::ByteVector> raw_bytes_ptr,
const base::Closure& on_flush_complete);
// Run on the I/O thread to start loading the savegame.
void InitializeOnIOThread();
// Called by the destructor, to ensure we destroy certain objects on the
// I/O thread.
void ShutdownOnIOThread();
// Runs on the I/O thread to write the database to the savegame's persistent
// storage.
void FlushOnIOThread(scoped_ptr<Savegame::ByteVector> raw_bytes_ptr,
const base::Closure& on_flush_complete);
// Savegame options passed in to SavegameThread's constructor.
Savegame::Options options_;
// On initialization, we'll read from the existing savegame file to get
// the latest data. This holds a reference to that data, but is released
// as soon as GetLoadedRawBytes() is called for the first time.
scoped_ptr<Savegame::ByteVector> loaded_raw_bytes_;
// The database gets loaded from disk. We block on returning a SQL context
// until storage_ready_ is signalled.
base::WaitableEvent initialized_;
// Storage I/O (savegame reads/writes) runs on a separate thread.
scoped_ptr<base::Thread> thread_;
// Interface to platform-specific savegame data.
scoped_ptr<Savegame> savegame_;
// How many flush failures have occurred since the last successful flush.
// Flushes (storage writes) may sometimes fail, but we want to make sure
// they're not consistently failing.
int num_consecutive_flush_failures_;
} // namespace storage
} // namespace cobalt